Traffic protection apparatus



June 1, 1948. H. A. TALBERT TRAFFIC PROTECTION APPARATUS Filed Jan. 25, 1947 u Q \w ww mmvroa ffezzpy mlbafl. BY

Patented June 1, 1948 um I so S TATES PATENT oFiF'rc E 2,442.73 'TRAFFw rRoErEoTIoNAPPARATUS Henry A. Talbert, Glen Rock,N.J.,"assigfior"to The Union Switchand Signal Company, Swissvale, Pa., acorporation of'Pennsylvania Application January 25, 1947," Seria l l To. 724;321 '7'"Claims. (01.24641) My invention relates to traffic protection apparatus, and particularly to apparatus for-pr0 viding crossover protection for trains moving along railway tracks which 'are interconnected by a crossover track through hand-operated trackswitch'es.

A requisite for crossover protection apparatus is'that it must be so arranged that a car or locomotive, while occupying a crossover such. for'exainple, as one connecting two main tracks, while the switches are in the normal position for train movements along'the main tracks, will cause asignal 'for'ea'chmain trackto indicate stop if the car or "locomotive is withi'n'fouling distance of that main track. In 'crossoverprotection schemes embodying track circuits, ens characteristic should therefore be high shunting sensitivity in order to insure that the crossover'track circuits will be shunted if the crossover track has high contact resistance "due to intrequency of trai'n'movements overthe crossover.

One feature of my invention is the provision of improved means for obtaininghigh shunting sensitivity throughdetermination'of the condition of occupancy of a crossover track by the picking up of a track relay'instead of by release of a track relay. With this arrangement, a. coinparatively high voltage may be applied to the traclccircuit for a brief period of time. The use 'of'suchhig'her voltagenas also been found to -*impreve s'huntirlg'sensitivity'of a track circuit.

ment over that which isdisclosed in Figs. land 2, of the copendin'g application,'-Se'rial "N0. 671,191, filed May 21, 1946, by Lowell B. Yarbroug nror Trai'fic' protection apparatus. (Lertain features disclosed in the'prese'nt'case are claimedbroadly in the Yarbrough application.

'I'shall describe one form of apparatus 'embodying my invention, and shallthen point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view'sliowing one form of'apparatus embodying my'invention, in which twonormallydeenergized track-circuits are provided for 'a crossover track and are arranged to become energizedfor a brief period of time only when the switches of the crossover track are restored'fromthe reverse to the normalpos'ition and when the crossover track is unoccupied.

"Similar reference characters refer to similar parts in the drawing.

-In'thedrawing, contacts operated by the verr- The apparatus of my invention is an improveous relays "or the trad: switches are identified bynui'nbers, such numbers having distinguishin'g "prefixes-from wiiichthey are separated by a "dash whn" thecontacts "are shownapart from the relay'by whichtiiey 'areoperated. The prefix 'for" each oftlies'e contact 'nuinlrie'rs comprises the "reference 'charactr *for' the respective relay by which "the. contact 'is operated. For example, contact SP-=19, shown "adjacent the symbol for relay 'lR,-isidentifled by the'numher 19 separated by a dash from the prefix "SP which is the "reference character for relay sP by which this "contact 'is operated.

Referringto'the"drawing, a'stret'ch of railway is shown comprising we inaimtra'cks designated by'the referencecharacters I'I' 'and2T, respectively, "connected with eachbther "by a' crossover track "through handmperated switches IW and 2W, respectively. Thecrossovertfaak isdivided y insulated joints '2 'into two sections l X and 2X.

"A track circuit is provided 'for section 1X including a suitable *source "of current such as a'batteryflQgend the control winding of 'a tracli relay IR. A'tfack 'circuit is also provided for section '2Xinc1uding"a battery "2Q, and'the controlwindiiigofatrack'relay2R. Relays IR and 2R are normally deefiergized.

A circuit controller l C, having "a plurality of contacts, is "operated in conjunction with "switch I'W. "Each of the. contacts is closed in a'normalposition, as shown in the drawing, when switch IW is 'in its normal position. A similar circuit 'co'ntroller 2C is operated in conjunction with-switch2W.

A 'stitzlrrelay SR isnorm'aHy "energized by a stick circuit including contacts of circuit controllers lCan'dZC.

A repeater relay SP, whichis madeslowreleasing by *a resistant-4 connected in'multiple with its control winding, is controlledby a back contact of relay SR.

'Frontoontactsbf relay 'SR and'back contacts of relay SP- are "included in signal control circuits 'for'tracks "lT'and 2T.

As shown'in'the 'diawingall parts of the apparatus are in .the normalf'condition, that is, each of the-"switches IW and 2W is in its normal positionfor a train'riioveme'nt along main track IT 'or'2T, "respectively; thetrack circuits for sections IX and 2X are open, "andhence track relays "IR and 2R are deenergized; relay SR is energized by it'sstik "circuit; and relay SP is deener'gi'z'ed. y t

The stick "circuit by which rela 'SR is energized passes from terminal B of a suitable source of current, through contact 3 of switch IW closed in the normal position, contact 4 of switch 2W closed in the normal position, contact 5 of relay SR, winding of relay SR, contact I of switch 2W, and contact 8 of switch IW to terminal N of the same source of current.

With relay SR energized and relay SP 'deenergized, contact 9 of relay SR and contact III of relay SP are closed in a signal control circuit for track IT. Similarly, contact II of relay SR and contact I2 of relay SP are closed in a signal control circuit for track 2T.

In tracing the operation of the apparatus in detail, I shall assume that a trainman reverses" switch IW, thereby opening contacts 3 and 8 of circuit controller IQ of switch I-W'inthenormaL position, and thus disconnecting the sourceof current from the circuit for relay SR and causing relay SR to become deenergized, and, at the same time, contacts I8 and 2| of switch IW open in their normal position in the track circuit for section IX. When relay SR becomes deenergized, its contacts Band II open the signal control circuits, thereby causing the signals for tracks IT and 2T to indicate stop. With relay SR deenergized, a circuit is completed for energizing relay SP, this circuit passing from terminal B, through contact I3 of relay SR, and the winding of relay SP in multiple with resistor I4, to terminal N;

Relay SP, upon thus becoming energized, opens its contacts I0 and I2 in the signal control circuits which are, however, already open at contacts. 9 and II of relay SR, as just described. Relay SP, upon becoming energized, closes contacts in the track circuits for sections IX and 2X, but these track circuits will remain open as longas switch IW is left in the reverse position.

After reversing switch IW, the trainman will also reverse switch 2W, thereby opening its contacts 4 and I in the circuit for relay SR and contacts I I and 22 in the track circuit for section IX.

I shall further assume thata train moves over the crossover, but that a car is left standing in section IX, and that a trainman then restores switches IW and 2W to the normal position; The track circuit for section IX will now be closed, passing from battery IQ, through a resistor I5, contact SP-IIS, contact I! of switch 2W closed in the normal position, contact I8 of switchIW closed in the normal position, rail Ia of section IX, contact SP-IS, Winding of relay IR, resistor 20, rail lb of section IX, contact 21 of switch IW closed in the normal position, and contact 22 of switch 2W closed in the normal position, back to battery IQ. Although this track circuit is now closed, relay IR will be shunted by the car in section IX, and will therefore not become energized.

I shall now assume that a trainman again reverses the switches for removal of the car from section IX, and that after thexcar'is one, he again returns both switches [W and 2W to the normal position. 'The circuit previously traced for relay IR will now again be closed, and relay IR will become energized, thereby completing a circuit for relay 2R, passing from battery 2Q, through a resistor 23, contacts SP24 and I R-25, rail lb of section 2X, resistor 26, winding of relay 2R, contact SP2I, and rail Ia of section 2X, back to battery 2Q.

Relay 2R, upon thus becoming energized, will complete a pick-up circuit for relay SR, which is the same as the stick circuit previously traced for this relay except that it includes contact 6 of relay 2R instead of contact 5 of relay SR. Relay SR, upon becoming energized, opensthe circuit previously traced for relay SP, causing relay SP to become deenergized.

Relay SP, upon becoming deenergized, opens the circuits previously traced for relays IR and 2R, causing both these track relays to become deenergized. Relay SR will now, however, remain energized by its stick circuit. The signal control circuits for tracks IT and 2T will now again be closed through front contacts of relay SR and back contacts of relay SP, as previously described.

Although'I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In traffic protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track through a first switch and a second switch, and in which said crossover track is divided into a first section adjacent said first switch and a second section adjacent said second switch, the combination comprising, a stick relay, a slow release relay, a track circuit for said first section including a suitable source of current and a track relay and controlled by a front contact of said slow release relay and by normally closed contacts of said first and second switches, a track circuit for said second section including a suitable source of current and a second track relay and controlled by front contacts of said slow release relay and said first track relay, a pick-up and a stick circuit for said stick relay each controlled by normally closed contacts of said first and second switches and said pick-up circuit also controlled by a front contact of said second track relay, a circuit controlled by a back contact of said stick relay for energizing said slow release relay, and a signal control circuit for each of said main tracks each controlled by a front contact of said stick relay and by a back contact of said slow release relay.

2. In traffic protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track through a first switch and a second switch, the combination comprising, a stick relay, a slow release relay, a track circuit for said crossover track including a suitable source of current and a track relay and controlled by a front contact of said slow release relay and including normally closed contacts of said first and second switches, a pick-up and a stick circuit for said stick relay each controlled by normally closed contacts of said first and second switches and said pick-up circuit also controlled by a front contact of said track relay, a

circuit controlled by aback contact of said stick relay for controlling said slow release relay, and means including a front contact of said stick relay and a back contact of said slow release relay for controlling signal control circuits for said main tracks.

3. In traflic protection apparatus for a stretch of auxiliary track connected with a main track by a switch having a normal position for traffic movements along said main track and a reverse position for traffic movements over said auxiliary track, the combination comprising, a stick relay, a slow release relay, a track circuit for said auxiliary track including a suitable source of current and a track relay and controlled by a front contact of said slow release relay and including a normally closed contact of said switch, a pick-up and a stick circuit for said stick relay controlled by a normally closed contact of said switch and said pick-up circuit also controlled by a front contact of said track relay, a circuit controlled by a back contact of said stick relay for controlling said slow release relay, and signal control means including a front contact of said stick relay and a back contact of said slow release relay.

4. In tralfic protection apparatus for a stretch of auxiliary track connected with a main track by a switch having a normal position for traiiic movements along said main track and a reverse position for traffic movements over said auxiliary track, the combination comprising, a stick relay, a track circuit for said auxiliary track including a suitable source of current and a track relay and controlled by a back contact of said stick relay and including a normally closed contact of said switch, a pick-up and a stick circuit for said stick relay each controlled by a normally closed contact of said switch and said pick-up circuit also controlled by a front contact of said track relay, and signal control means including a front contact of said stick relay.

5. In traific protection apparatus for a stretch of auxiliary track connected with a main track by a switch having a normal position for traffic movements along said main track and a reverse position for traffic movements over said auxiliary track, the combination comprising, a stick relay, train responsive means for said auxiliary track controlled by a back contact of said stick relay and including a normally closed contact of said switch, a pick-up and a stick circuit for said stick relay controlled by a normally closed contact of said switch and said pick-up circuit also controlled by a contact closed by said train responsive means when said auxiliary track is unoccupied, and signal control means including a front contact of said stick relay.

6. In traflfic protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track through a first switch and a second switch, and in which said crossover track is divided into a first section adjacent said first switch and a second section adjacent said second switch, the combination comprising, a stick relay, a slow release relay, train responsive means deenergized by a train in said first section and controlled by a front contact of said slow release relay and by normally closed contacts of said first and second switches, other train responsive means deenergized by a train in said second section and controlled by front contacts of said slow release relay and said first train responsive means, a pick-up and a stick circuit for said stick relay each controlled by normally closed contacts of said first and second switches and said pickup circuit also controlled by a front contact of said second train responsive means, a circuit controlled by a back contact of said stick relay for energizing said slow release relay, and signal control means including a front contact of said stick relay and a back contact of said slow release relay.

7. In traific protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track through a first switch and a second switch, and in which said crossover track is divided into a first section adjacent said first switch and a second section adjacent said second switch, the combination comprising, a stick relay, train responsive means deenergized by a train in said first section and controlled by a back contact of said stick relay and by normally closed contacts of said first and sec- 0nd switches, other train responsive means deenergized by a train in said second section and controlled by a back contact of said stick relay and by a front contact of said first train responsive means, a pick-up and a stick circuit for said stick relay each controlled by normally closed contacts of said first and second switches and said pick-up circuit also controlled by a front contact of said second train responsive means, and signal control means including a front contact of said stick relay.

HENRY A. TALBERT, 

